Method of controlling test films in biochemical analysis apparatus

ABSTRACT

In a biochemical analysis apparatus a frameless dry chemical analysis film having a reagent layer formed on a support sheet is taken out from a cartridge storing therein a plurality of the frameless chemical analysis films, applied with a sample liquid, inserted into an incubator and taken out from the incubator and at least a part of these steps and film transferring steps between these steps is effected with the film held by a suction pad. A change of pressure in the suction pad when it attracts the film under a suction force is measured and the attracting state of the suction pad is judged on the basis of the result of the measurement. The part of the steps which is effected with the film held by the suction pad is controlled on the basis of the judgment.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a biochemical analysis apparatus and a methodof controlling same, and more particularly to controlling a biochemicalanalysis apparatus in which a frameless dry chemical analysis filmhaving a reagent layer containing a reagent whose optical densitychanges through a chemical reaction, a biochemical reaction, animmunoreaction or the like with a specific biochemical componentcontained in a sample liquid such as blood or urine is taken out from acartridge, transferred to a sample liquid spotting position, appliedwith a sample liquid by spotting in the sample liquid spotting position,transferred to an incubator, inserted into the incubator and taken outfrom the incubator and at least one of these steps is effected with thefilm held by a suction means.

2. Description of the Prior Art

There has been put into practice a "dry-to-the-touch" chemical analysisfilm with which the content of a specific chemical component containedin a sample liquid, the activity thereof or the content of a solidcomponent can be quantitatively analyzed by only spotting a droplet ofthe sample liquid on the film. One example of a dry chemical analysisfilm, there has been known an integrated multi-layered chemical analysisfilm (sometimes referred to as "multi-layered chemical analysiselement") comprising a support sheet of organic polymer and at least onereagent layer which contains a reagent and is formed on the supportsheet. A spreading layer is sometimes provided over the reagent layer.Further, a dry chemical analysis element which is formed of filter paperand has one or more layers has been proposed and partly put intopractice.

When quantitatively analyzing the chemical components or the likecontained in a sample liquid using such a dry chemical analysis film, adroplet of the sample liquid is typically spotted on the film (on thespreading layer when the film is provided with a spreading layer and onthe reagent layer when the film is not provided with a spreading layer)and is held at a constant temperature for a predetermined time(incubation) in an incubator so that a coloring reaction occurs. Theoptical density of the color formed by the coloring reaction is thenoptically measured. That is, a wavelength is pre-selected according tothe combination of the component to be analyzed and the reagentcontained in the reagent layer of the film. Measuring light containingthis wavelength is then projected onto the film and the optical densityof the film is measured. Then the concentration or the activity of thecomponent to be analyzed is determined on the basis of the opticaldensity using a calibration curve which represents the relation betweenthe concentration of the biochemical component and the optical density.

The integrated multi-layered chemical analysis film is generally in theform of a film chip of a predetermined shape, e.g., as square orrectangle. The film chip is sometimes provided with a frame of organicpolymer and used in the form of a chemical analysis slide. The framehelps to flatten the film chip which is apt to curl or warp in a drystate, thereby facilitating automated handling of the chemical analysisfilm. However use of the chemical analysis slide is disadvantageous inthat the chemical analysis slide is larger than the chemical analysisfilm chip by the size of the frame and accordingly parts of thebiochemical analysis apparatus must be larger, which obstructs reductionin size of the biochemical analysis apparatus and at the same timeresults in reduction of the overall throughput capacity of thebiochemical analysis apparatus. Thus, the use of the chemical analysisslides adds to the cost of measurement.

In a biochemical analysis apparatus we have proposed previously, thefilm chip is used without a frame (hereinafter referred to as "framelesschemical analysis film"). A plurality of the frameless chemical analysisfilms are loaded in a cartridge and the cartridge is loaded in achemical analysis film supplier for a biochemical analysis apparatus.The frameless chemical analysis films are taken out from the cartridgein the supplier one by one by use of a suction pad as disclosed, forinstance, in our patent applications such as Japanese Patent ApplicationNo. 5(1993)-177056 and U.S. Patent Application No. 08/273,131, now U.S.Pat. No. 5,534,224.

Since the frameless chemical analysis film is curled or warped into aroof tile-shape in the dry state, taking out the film by attracting itunder a suction force by the suction pad as described above should bethe best way of taking out the film from the cartridge without damagingthe surface of the film.

In the biochemical analysis apparatus, the frameless chemical analysisfilm taken out from the cartridge is transferred to the spottingposition and a sample liquid is spotted on the film. Thereafter the filmis transferred to the incubator and inserted into a cell in theincubator. After a predetermined incubation, the optical density of thebiochemical substance is measured, and the film is taken out from thecell and discarded in a predetermined discarding box. In many of thesesteps, a plurality of suction means, e.g., suction pads andhorseshoe-like suction means, are used to hold the frameless chemicalanalysis film. The suction pads and the horseshoe-like suction means aredisclosed in detail in the Japanese patent applications identified aboveand the like.

Since the suction means must surely hold the frameless chemical analysisfilm which is light in weight and small in thickness, it is necessary toconstantly keep the suction force at an optimal level. However, thesuction force can be easily changed by various causes, such as a clog inthe suction pipe from dust, defects in the vacuum pump, valves, filtersor the like, and/or cracking in the suction means etc.

Further, since many suction means are used in the biochemical analysisapparatus, it is difficult for the operator to constantly check thesuction force of each suction means.

SUMMARY OF THE INVENTION

In view of the foregoing observations and description, the primaryobject of the present invention is to provide a method of controlling abiochemical analysis apparatus which can constantly watch the attractingstate of the suction means.

Another object of the present invention is to provide a method ofcontrolling a biochemical analysis apparatus which can inform theoperator when the attracting state of the suction means is abnormal.

Still another object of the present invention is to provide a method ofcontrolling a biochemical analysis apparatus which can quickly removedust or the like when the attracting state of the suction means isabnormal due to dust, etc. clogging the suction means.

In accordance with the present invention, there is provided a method ofcontrolling a biochemical analysis apparatus in which a frameless drychemical analysis film having a reagent layer formed on a support sheetis taken out from a cartridge, applied with a sample liquid, insertedinto an incubator and taken out from the incubator, and at least a partof these steps and film transferring steps between these steps iseffected with the film held by a suction means, is

Furthermore a change of pressure in the suction means is measured whenthe suction means attracts the film under a suction force, judging theattracting state of the suction means on the basis of the result of themeasurement and controlling the part of the steps which is effected withthe film held by the suction means on the basis of the judgment.

In one embodiment of the present invention, the attracting state of thesuction means is indicated by a visual and/or acoustic means such as amonitor, a LED or a buzzer.

In another embodiment of the present invention, air is blown outside thesuction means through the portion on which the suction means attractsthe film.

In this embodiment, air may be blown at any timing. For example, air maybe blown when an abnormality occurs or may be blown at regularintervals.

The term "attracting state of the suction means" means the state ofmaintenance of the suction means itself and the state of attraction ofthe suction means for the film.

In the method of the present invention, the change of pressure in thesuction means (e.g., the suction pads and the horseshoe-like suctionmeans used in the biochemical analysis apparatus) when the suction meansattracts the frameless chemical analysis film under suction force.

The change of the pressure shows a peculiar pattern according to theattracting state of the suction means. For example, when the attractingforce of the suction means is normal and the state of attraction of thesuction means for the film is normal, the pressure in the suction meansis lowered to a predetermined value within a predetermined time afterinitiation of attraction of the suction means for the film, and thenkept at the predetermined pressure.

When a leak occurs in the vacuum pump or the vacuum line for the suctionmeans, or the vacuum line clogs, the pressure in the suction meanscannot be lowered to the predetermined value within the predeterminedtime after initiation of attraction of the suction means for the film.Further when the film is attracted to the suction means in a wrongposition, the pressure in the suction means fluctuates after it islowered to the predetermined pressure within the predetermined time.

Thus, the attracting state of the suction means can be known bymonitoring the change of the pressure in the suction means, and thebiochemical analysis apparatus can be properly controlled according tothe attracting state of the suction means. For example, the succeedingsteps of the biochemical analysis apparatus may be interrupted or thesuction means may be cleaned before the succeeding step when theattracting state of the suction means is abnormal.

Further when the attracting state is indicated by a visual and/oracoustic means such as a monitor, a LED or a buzzer, the operator caninstantly know that the attracting state of the suction means isabnormal and can quickly deal with the trouble.

Further, when air is blown outside the suction means through the portionon which the suction means attracts the film, dust or the like in thesuction means can be blown out, whereby maintenance of the suction meansis facilitated.

It is preferred that air be blown not only when an abnormality occursbut also at regular intervals.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a flow chart for illustrating the method of controlling abiochemical analysis apparatus in accordance with an embodiment of thepresent invention,

FIG. 2 is a schematic perspective view showing an example of abiochemical analysis apparatus for carrying out the method,

FIG. 3 is a perspective view showing spotting of the sample liquid onthe frameless chemical analysis film,

FIG. 4 is a perspective view showing the operation of taking out theframeless chemical analysis film from the cartridge,

FIG. 5 is a fragmentary perspective view of the film transfer member,

FIGS. 6A to 6C are schematic views for illustrating procedure fortransferring the film from the suction pad to the film transfer member,

FIG. 7 is a block diagram for illustrating the pressure detecting systemconnected to the suction pad, and

FIGS. 8A to 8D are graphs of various patterns of the pressure change inthe suction pad.

DESCRIPTION OF THE PREFERRED EMBODIMENT

In FIG. 2, a biochemical analysis apparatus 10 for carrying out themethod in accordance with an embodiment of the present inventioncomprises a film supplier 11 in which a plurality of virgin rectangularframeless chemical analysis films 1 are stored, an incubator 12 which isdisposed beside the film supplier 11 and incubates the framelesschemical analysis films 1 at a predetermined temperature for apredetermined time, a film transfer means 13 which transfers theframeless chemical analysis films 1 from the film supplier 11 to theincubator 12, a sample liquid supplier 14 in which a plurality of sampleliquids such as serum, urine or the like are stored, a spottingmechanism 15 which spots one of the sample liquids in the sample liquidsupplier 14 on the frameless chemical analysis film 1 on the way to theincubator 12, and a light measuring system 16 disposed below theincubator 12.

As shown in FIG. 3, the frameless chemical analysis film 1 comprises alight-transmissive support sheet 1a formed of plastic film such aspolyethylene terephthalate and a reagent layer 1b (including a spreadinglayer) formed on the support sheet 1a. If necessary, a wear-resistantprotective layer of fibrous material such as fabric may be formed on thereagent layer 1b. Such a protective layer may double as the spreadinglayer.

The dry frameless chemical analysis film 1 is apt to curl toward thereagent layer 1b in the dry state before spotting of the sample liquid,and the curvature varies depending on the dryness and the kind of thereagent layer 1b. The reagent layer 1b contains reagent (chemicalanalysis reagent or immunoassay reagent) which makes coloring reactionwhen it is mixed with a particular component in the sample liquidspotted by a nozzle tip 88 of the spotting mechanism 15 and is incubatedat a constant temperature for a predetermined time. A plurality of kindsof frameless chemical analysis films 1 having different reagent layers1b are prepared according to the items of analysis, e.g., the chemicalcomponents or solid components to be analyzed in the sample liquids.

The frameless chemical analysis films 1 are stored in cartridges 20(FIG. 4) for the respective items of analysis. In the cartridge 20, aplurality of the frameless chemical analysis films 1 are stacked withthe support sheets 1a facing downward. As shown in FIG. 1, the filmsupplier 11 is provided with a plurality of cartridge holding portions22a which are arranged in inner and outer circles on a disk-like support22 and a plurality of cartridges 20 loaded with the frameless chemicalanalysis films 1 are held in the respective cartridge holding portions22a. The support 22 is supported for rotation on a base portion 24 andis rotated by a motor not shown so that a predetermined cartridgeholding portion 22a is brought to a film takeout position where the filmtransfer means 13 takes out a frameless chemical analysis film 1 fromthe cartridge 20.

The support 22 is provided with a cover 25 which encloses inner space ofthe film supplier 11. The cover 25 is provided with a pair of openings25a provided with lids and the cartridges 20 can be taken out andinserted into the cartridge holding portion 22a through the openings25a. A dehumidifying agent holding portion 27 is formed in the support22 at the center thereof and a dehumidifying agent is loaded in thedehumidifying agent holding portion 27 through an opening 25b formed inthe cover 25. The opening 25b is provided with a lid. Thus the innerspace of the film supplier 11 is kept dry. A film takeout port (notshown) is provided in the lower surface of the cover 25 in the filmtakeout position and a shutter is provided to open and close the filmtakeout port. The shutter is opened when the frameless chemical analysisfilm 1 is taken out from the cartridge 20 and a suction pad 70 of thefilm transfer means 13 is inserted into the film supplier 11 through theshutter and takes out the lowermost film 1 in the cartridge 20.

The incubator 12 comprises a disk-like body portion 40 which issupported to be rotated by a drive mechanism 41 disposed below the bodyportion 40 at the center thereof. A plurality of cells 42 are providedin the body portion 40 at predetermined intervals in the circumferentialdirection thereof. The frameless chemical analysis films 1 are incubatedin the cells 42.

The film transfer means 13 for transferring the frameless chemicalanalysis film 1 from the film supplier 11 to the incubator 12 comprisessuction pad 70 which takes out the film 1 from the cartridge 20, ahorseshoe-like film transfer member 73 which receives the film 1 held onthe suction pad 70 from below the film 1 with the reagent layer 1bfacing upward and inserts the film 1 into the cell 42 in the incubator12 through an opening which opens sideways, and a suction member 76which moves in and out the cell 42 from below the cell and receives thefilm 1 held by the film transfer member 73 inside the cell 42.

As shown in FIG. 4, the suction pad 70 comprises a suction cup 70a whichis directed upward and attracts the lower side of the support sheet 1aof the frameless chemical analysis film 1. The suction cup 70a issupported on a base portion 70b which is moved back and forth and up anddown by a drive mechanism (not shown) and is connected to a suction pump(not shown) through a vacuum tube.

The suction pad 70 is moved upward into the cartridge 20 through anopening in the bottom of the cartridge 20 and attracts the lowermostframeless chemical analysis film 1 on the support sheet side thereof.Then the suction pad 70 is slightly moved downward to curl the lowermostfilm 1 and then horizontally moved to take out the film 1 from thecartridge through an opening 20a in the side wall of the cartridge withthe film 1 held in the curled state. Thereafter the suction pad 70 ismoved downward outside the film supplier 11 through the film takeoutport in the film supplier 11 and is moved toward the spotting positionwhere the sample liquid is spotted on the film 1.

As shown in FIG. 5, the film transfer member 73 is like a horseshoe inshape and has a flat upper surface. That is, the film transfer member 73is bifurcated in the front end portion to form a pair of arm portions73b extending on opposite sides of a cutaway portion 73a, and aplurality of suction holes 74 are formed to surround the cutaway portion73a and to open in the upper surface of the film transfer member 73. Thesuction holes 74 are connected to a suction pump (to be described later)through a vacuum tube 75. The base portion of the film transfer member73 is connected to a drive mechanism (not shown) to be inserted into thecell 42 in the incubator 12 through the opening thereof.

When the film transfer member 73 receives the film 1 from the suctionpad 70, the film transfer member 73 is moved toward the suction pad 70holding the film 1 as shown in FIG. 6A and is stopped in a positionwhere the suction pad 70 is in the cutaway portion 73a of the filmtransfer member 73 with the film 1 positioned above the cutaway portion73a as shown in FIG. 6B. Then the suction pad 70 is moved downward belowthe film transfer member 73 leaving the film 1 on the film transfermember 73 as shown in FIG. 6C. The film 1 left on the film transfermember 73 is held thereon under the suction force provided through thesuction holes 74 in the arm portions 73b and the base portion of thetransfer member 73. When the position of the suction pad 70 relative tothe film 1 held thereby is accurately controlled, the position of thefilm transfer member 73 relative to the film 1 can be accuratelycontrolled and a predetermined amount of the sample liquid can beaccurately spotted on the center of the reagent layer 1b of theframeless chemical analysis film 1 held by the film transfer member 73.

A film removing means 17 (FIG. 1) is disposed in the film removingposition of the incubator 12. The film removing means 17 comprises aremoving suction pad 81 which attracts the film 1 in the cell 42 whichhas finished with measurement and lifts it, a horseshoe-like filmremoving member 82 which receives the film 1 from the removing suctionpad 81 and transfers it outside the incubator 12 and a discardingsuction pad 83 which receives the film 1 from the film removing member82 and discards it into a discarding box 84.

The sample liquid supplier 14 comprises a turn table 85 which is rotatedby a drive mechanism 86. The turn table 85 holds a plurality of sampletubes 87 filled with sample liquids which are arranged along thecircumferential edge of the turn table 85 and is rotated to bring thesample tubes 87 to a sample liquid supplying position one by one. Aplurality of nozzle tips 88 which are mounted on a spotting nozzle 91 tobe described later are held on the turn table 85 inside the sample tubes87.

The spotting means 15 for spotting the sample liquid on the framelesschemical analysis film 1 to be transferred to the incubator 12 comprisesa spotting nozzle 91 which sucks and discharges the sample liquid, and anozzle tip 88 is demountably mounted on the nozzle 91. The nozzle 91 ismoved up and down and rotated by a drive mechanism 92. That is, thenozzle 91 sucks the sample liquid from the sample liquid supplier 14, ismoved to the film 1 held by the film transfer member 73, and then spotsthe sample liquid on the film 1. The nozzle tip 88 is changed every timethe sample liquid is changed.

The film 1 spotted with the sample liquid is transferred to theincubator 12 and incubated there.

After incubation for a predetermined time, the optical density of thereagent layer 1b is measured by the light measuring system 16 (FIG. 1)disposed below the incubator 12. The light measuring system 16 comprisessaid light measuring head 95 for measuring the optical density of thecolor formed by the coloring reaction between the reagent layer 1b andthe sample liquid. The light measuring head 95 projects measuring lightcontaining light of a predetermined wavelength onto the reagent layer 1bthrough the support sheet 1a and detects reflected light with aphotodetector. Light from a light source (lamp) 96 enters the lightmeasuring head 95 through a filter 97 and is caused to impinge upon thereagent layer 1b by the head 95. A plurality of kinds of the filters 97are mounted on a rotary disk 98 which is driven by an electric motor 99and one of the filters 97 is selected according to the item ofmeasurement.

The reflected light from the reagent layer 1b carries thereon opticalinformation (more particularly the amount of light) on the amount ofcoloring matter formed by the coloring reaction between the reagentlayer 1b and the sample liquid. The reflected light is received by thephotodetector and the optical information carried by the reflected lightis converted to an electric signal by the photodetector. The electricsignal is input into a determination section through an amplifier. Thedetermination section determines the optical density of the coloringmatter formed by the coloring reaction between the reagent layer 1b andthe sample liquid on the basis of the level of the electric signal anddetermines the concentration of a predetermined chemical component inthe sample liquid.

As can be understood from the description above, in the biochemicalanalysis apparatus 10, there are used many suction means, e.g., thesuction pads 70, 76, 81 and 83 and the horseshoe-like transfer members73 and 82.

This is because it is difficult to use the film holding means for theconventional chemical analysis system as it is to handle the curledframeless chemical analysis film 1 in an automated system. That is, thestep of taking out the films 1 one by one from the cartridge in the filmsupplier 11, the step of spotting the sample liquid on the film 1 andtransferring it to the incubator 12, the step of inserting the film 1into the cell 42, the step of taking out the film 1 from the cell 42after a predetermined time and discarding it and the like should beeffected taking into account the curled shape of the film 1. Further useof such suction means is effective to handle the frameless chemicalanalysis film 1 without damaging the surface of the film 1.

However the suction means are connected to a vacuum pump through avacuum line and when the vacuum line clogs with dust or the like or aleak occurs in the vacuum line or the vacuum pump, the attracting forceof the suction means can be reduced, which makes it difficult to effectthe steps described above in an optimal manner. Further, shift of thefilm 1 attracted by the suction means from the predetermined positiongives rise to problems in the succeeding steps. Since many suction meansare employed in the biochemical analysis apparatus 10, it is difficultfor the operator to constantly check the states of the suction means andthe position of the film 1 one by one.

In order to overcome these problems, a pressure detecting circuit and apressure judging means are connected to the vacuum line for each suctionmeans as shown in FIG. 7 and the attracting state of each suction meansis watched.

FIG. 7 shows an attracting state judging system connected to the vacuumline for the suction pad 70 for taking out the film 1 from the cartridge20. Similar attracting stake judging systems are connected to the othersuction means, the suction pads 76, 81 and 83 and the horseshoe-liketransfer members 73 and 82.

As described above, the suction pad 70 attracts the lowermost film 1 inthe cartridge 20 by the suction cup 70a and moves in the transversedirection of the cartridge to take out the film 1 from the cartridge 20.The base portion 70b of the suction pad 70 is connected to a vacuum pump(P1) 101 and a pressure pump (P2) 110 by way of a pipe 100. A valve 102,a filter 103 and a pressure detecting portion 104 are provided betweenthe vacuum pump 101 and the suction pad 70. A pressure sensor 105 isconnected to the pressure detecting portion 104. The pressure detectedby the pressure sensor 105 is read by a pressure detecting circuit 106and the attracting state of the suction pad 70 is judged by anattracting state judging section 107 on the basis of the pattern ofchange of the pressure detected by the pressure sensor 105. When it isdetermined that the attracting state of the suction pad 70 is abnormal,one of LEDs 108A to 108C is lit and a predetermined sound is emittedfrom a buzzer 109 according to the degree of abnormality.

An air accumulating chamber 111 and a valve 112 are provided between thesuction pad 70 and the pressure pump 110. The valve 112 is closed whenthe vacuum system is operated and is opened to blow off the dust or thelike if any. When the valve 112 in the pressure system is opened thevalve 102 in the vacuum system is closed.

The pressure system may be operated at any timing. For example, thepressure system may be operated when the attracting state judgingsection 107 judges that the attracting state of the suction pad 70 isabnormal or at regular intervals.

There is a predetermined correlation between the pattern of pressurechange and the attracting state of the suction pad 70.

For example, when the suction pad 70 begins to attract the film 1 attime t1, and the pressure in the suction pad 70 is not higher than P_(A)(a pressure at which the suction pad 70 can attract the film 1 under asufficient force) at time t2 and is kept not higher than P_(A) at timet3 as shown in FIG. 8A, the attracting state of the suction pad 70 isnormal.

When the suction pad 70 begins to attract the film 1 at time t1, and thepressure in the suction pad 70 is still higher than a limit pressureP_(B) (the critical pressure higher than which the suction pad 70 cannotattract the film 1) at time t2 as shown in FIG. 8B, the attracting stateof the suction pad 70 is abnormal. That is, the vacuum system clogs withdust or the like or cracking is produced in the vacuum system.

When the suction pad 70 begins to attract the film 1 at time t1, and thepressure in the suction pad 70 is between P_(B) and P_(A) at time t2 andis kept at a pressure between P_(A) and P_(B) at time t3 as shown inFIG. 8C, it may be considered that the vacuum pump 101 has deteriorated,and prompt repair or replacement of parts of the vacuum pump 101 isnecessary though the suction pad 70 can still attract the film 1.

Further, when the suction pad 70 begins to attract the film 1 at timet1, and the pressure in the suction pad 70 is not higher than P_(A) attime t2 and subsequently increases to be higher than P_(A) at time t3 asshown in FIG. 8D, it may be considered that though the vacuum system isoperating normally, some abnormality, e.g., the film 1 is displaced fromthe predetermined position during the step of taking out the film 1 fromthe cartridge, occurs and the cause of the abnormality should be quicklyremoved.

The attracting state judging section 107 comprises a computer andvarious patterns of pressure change such as shown in FIGS. 8A to 8D arestored in a memory. The computer compares the pattern of pressure changeinput thereinto with the patterns of pressure change stored in thememory and selectively energizes the LEDs 8A to 8C and the buzzer 109 onthe basis of the result of the comparison.

In this particular embodiment, the computer of the attracting statejudging section 107 doubles as a controller for controlling the suctionpad 70 and the like.

The operation of the computer will be described with reference to theflow chart shown in FIG. 1.

The computer first causes the suction pad 70 to move upward until thesuction pad 70 abuts against the lowermost film 1 in the cartridge 20through the opening in the bottom of the cartridge 20 and then stops thesuction pad 70 there. (steps S1 and S2)

Then the computer causes the pressure detecting circuit 106 to initiatedetecting the pressure P in the suction pad 70 (step S3) and causes thevacuum pump 101 to operate (step S4).

The computer watches the detected pressure P from the pressure detectingcircuit 106 and judges whether the pressure P is not higher than P_(A)at time t2. (step S5) It is assumed that the vacuum pump 101 is causedto operate at time t1.

When it is determined in step S5 that the pressure P is not higher thanP_(A) at time t2, the computer determines whether the pressure P ishigher than P_(A) at time t3. (step S6)

When it is determined in step S6 that the pressure P is higher thanP_(A) at time t3, the computer judges that the attracting state of thesuction pad 70 is normal (corresponding to the pattern of pressurechange shown in FIG. 8A), and causes the suction pad 70 to move in thetransverse direction of the cartridge 20 to take out the film 1 throughthe film take-out port 20a of the cartridge 20. (step S7)

On the other hand, when it is determined in step S5 that the pressure Pis higher than P_(A) at time t2, the computer determines whether thepressure P is not higher than P_(B) at time t2. (step S8) When it isdetermined in step S8 that the pressure P is higher than P_(B) at timet2, the computer judges that the attracting state of the suction pad 70is abnormal to such an extent that the step of taking out the film 1cannot be successfully continued (corresponding to the pattern ofpressure change shown in FIG. 8B), and causes the LED 108A to light upand the buzzer 109 to emit a predetermined sound (e.g., continuoussound). (step S9) Since the step of taking out the film 1 cannot becontinued in this case, the computer stops the vacuum pump 101, causesthe pressure detecting circuit 106 to interrupt detection of thepressure and lowers the suction pad 70 to the original position. (stepS10)

The operator can know that the suction pad 70 is in a serious troublefrom the LED 108A and the sound of the buzzer 109 and can properly andquickly deal with the trouble.

When it is determined in step S8 that the pressure P is not higher thanP_(B), the computer judges that the attracting force of the suction pad70 is acceptable though not sufficient (corresponding to the pattern ofpressure change shown in FIG. 8C), and causes the LED 108B to light upand the buzzer 109 to emit a predetermined sound (e.g., long on/offsound), thereby informing the operator of the need to promptly check thevacuum system. (step S11) Then the computer causes the suction pad 70 tomove in the transverse direction of the cartridge 20 to take out thefilm 1 through the film take-out port 20a of the cartridge 20. (step S7)

When it is determined in step S6 that the pressure P is higher thanP_(A) at time t3, the computer determines whether the pressure P ishigher than P_(B) at time t3. (step S12) When it is determined in stepS12 that the pressure P is not higher than P_(A) at time t3, it may beconsidered that the film 1 is once properly attracted by the suction pad70 in the predetermined position and the pressure P is lowered belowP_(A) and the film 1 is subsequently shifted from the predeterminedposition and the pressure P is increased to some extent (correspondingto the pattern of pressure change shown in FIG. 8D).

In this case, the computer causes the LED 108C to light up and thebuzzer 109 to emit a predetermined sound (e.g., a short on/off sound)(step S13) and then idles until P lowers below the pressure P_(A) (stepS14). When the operator removes the cause of the abnormality and Plowers below the pressure P_(A), the computer causes the suction pad 70to move in the transverse direction of the cartridge 20 to take out thefilm 1 through the film take-out port 20a of the cartridge 20. (step S7)

When it is determined in step S12 that the pressure P is higher thanP_(B) at time t3, the computer judges that a serious abnormality, e.g.,that the film 1 falls off the suction pad 70, occurs and causes the LED108A to light up and the buzzer 109 to emit the predetermined sound instep S7 as in the case where the pressure P does not ever lower belowthe pressure P_(A). (step S9)

Although, in the embodiment described above, the attracting state of thesuction pad 70 is judged from the pattern of the pressure change in thevacuum system, other states may be judged from the pattern of thepressure change in the vacuum system.

For example, by watching the pressure changes in the vacuum systems forthe suction pad 70 and the transfer member 73 when the film 1 istransferred from the former to the latter, it can be judged what timingthe film 1 is transferred or whether the film 1 is surely transferred.

The method of the present invention may be variously modified withoutbeing limited to the embodiment described above. For example, thepressure system may be eliminated from the apparatus shown in FIG. 1 andthe attracting state may be judged on the basis of patterns of pressurechange other than those shown in FIGS. 8A to 8D.

Although, in the embodiment described above, the state of abnormality isindicated by use of LEDs, the state of abnormality may be indicated byuse of a monitor.

As can be understood from the description above, in accordance with thepresent invention, the pressure change in the vacuum system for thesuction means such as the suction pads or the horseshoe-like transfermembers is monitored and the attracting state of the suction means isjudged on the basis of the pattern of the pressure change, and thebiochemical analysis apparatus is controlled according to the attractingstate of the suction means thus judged. Accordingly, in the biochemicalanalysis apparatus in which a suction means is employed which is apt tofail due to the adhesion of dust, a crack in the line, etc., the failurecan be detected soon and dealt with properly, whereby the biochemicalanalysis apparatus can be smoothly operated.

Further, when the attracting state is indicated by a visual and/oracoustic means such as a monitor, a LED or a buzzer, the operator caninstantly know that the attracting state of the suction means isabnormal and can quickly deal with the trouble.

Further, when air is blown outside the suction means, dust or the likein the suction means can be blown out, whereby the biochemical analysisapparatus can be further smoothly operated.

What is claimed is:
 1. A method of controlling a biochemical analysisapparatus comprising the steps of:moving an analysis film between aplurality of processing stations, and temporarily holding said analysisfilm at said processing stations, wherein at least two of said movingand holding steps are performed using at least two of a plurality ofindependent suction means, measuring a pressure in said independentsuction means at least two predetermined times after said independentsuction means begins attracting said film under a suction force, judgingan attracting state of said independent suction means on the basis ofthe result of the measurements and a predetermined set of attractingstate parameters wherein said attracting state parameters are used toindicate at least two different abnormal states, and controlling saidmoving and holding steps on the basis of the judgment.
 2. A method ofcontrolling a biochemical analysis apparatus as defined in claim 1 inwhich the steps of judging the attracting state of the suction means isperformed on the basis of a change of pressure with time.
 3. A method ofcontrolling a biochemical analysis apparatus as defined in claim 2 inwhich the attracting state of the suction means is indicated by a visualand/or acoustic means.
 4. A method of controlling a biochemical analysisapparatus as defined in claim 1 in which the attracting state of thesuction means is indicated by a visual and/or acoustic means.
 5. Amethod of controlling a biochemical analysis apparatus as defined in anyone of claims 1 to 4 in which air is blown outside the suction meansthrough a portion of said suction means on which the suction meansattracts the film when judgment that the attracting state is abnormal ismade according to said predetermined attracting state parameters.
 6. Amethod in accordance with claim 1, wherein said judging step furthercomprises the step of determining whether said independent suction meansis at least partially obstructed.
 7. A method in accordance with claim1, wherein said judging step further comprises the step of comparing apattern of pressure measurements at said predetermined times with apredetermined pattern of pressure values for said predetermined times,said predetermined pattern defined by said predetermined set ofattracting state parameters.
 8. A method of controlling a biochemicalanalysis apparatus comprising the steps of:moving an analysis film toand from at least one processing station, and temporarily holding saidanalysis film at said processing station, wherein at least one of saidmoving and holding steps is performed using at least one suction means,measuring a pressure in said suction means at least two predeterminedtimes after said suction means begins attracting said film under asuction force, judging an attracting state of said suction means on thebasis of the result of the measurements and a predetermined set ofattracting state parameters wherein said attracting state parameters areused to indicate at least two different abnormal states, and controllingsaid apparatus on the basis of the judgment.